BioLab
Lab calculators that show their work
155 calculators for the arithmetic of bench science, from making a solution to counting cells. Every one states the formula it uses, works an example you can check by hand and lists its assumptions. Calculations run in your browser and nothing you enter is stored.
Solutions & Chemistry
Molarity, dilutions, unit conversion, recipes, buffers and standard curves
Molarity CalculatorMass, concentration or volume for a molar solutionOpen calculatorDilution Calculator (C1V1 = C2V2)Stock and diluent volumes for any dilutionOpen calculatorSerial Dilution CalculatorTransfer volumes and the concentration in every tubeOpen calculatorMolecular Weight CalculatorMolar mass and composition from a chemical formulaOpen calculatorPercent Solution Calculator% w/v, % v/v and % w/w solutionsOpen calculatorBuffer Calculator (Henderson-Hasselbalch)Acid and base amounts for a buffer at a target pHOpen calculatorDilution Factor and Ratio CalculatorFold dilution, 1 : N notation and the volumes behind itOpen calculatorMolality CalculatorMoles of solute per kilogram of solventOpen calculatorNormality CalculatorEquivalents per litre for acids, bases and redox reagentsOpen calculatorppm and ppb CalculatorParts per million and per billion, by mass or in dilute solutionOpen calculatorConcentration Unit ConverterMolar, mass per volume, mg/dL and % w/vOpen calculatorReagent and Buffer Recipe CalculatorWeigh-out masses and stock volumes for a whole recipeOpen calculatorMaster Mix CalculatorScale any reaction recipe to a batch, with overageOpen calculatorMixing Solutions CalculatorConcentration of a mixture, or volumes to hit a targetOpen calculator
Molecular Biology
Nucleic acid quantification, sequence tools, PCR and qPCR
DNA and RNA Concentration Calculator (A260)Nucleic acid concentration and purity from absorbanceOpen calculatorDNA Dilution CalculatorDilute a DNA or RNA stock to a working concentrationOpen calculatorGC Content CalculatorGC percentage and base composition of a sequenceOpen calculatorReverse Complement ToolReverse, complement or reverse-complement a sequenceOpen calculatorPrimer Tm Calculator (Four Methods)Primer melting temperature by four accepted methods, side by sideOpen calculatorDNA and RNA Molecular Weight CalculatorExact molecular weight of an oligo or sequence, ss or dsOpen calculatorDNA and RNA Molarity CalculatorConvert ng/µL to nM, pmol per µg and molecules per µLOpen calculatorDNA Copy Number CalculatorNumber of copies in a mass of plasmid, amplicon or genomeOpen calculatorFASTA Sequence AnalyzerLength, GC, base counts and CpG ratio for one or many sequencesOpen calculatorDNA to RNA Converter (Transcription)Transcribe DNA to mRNA, back to DNA, or to cDNAOpen calculatorDNA Translation Tool (DNA to Protein)Translate in any of six reading frames with a chosen genetic codeOpen calculatorCodon Usage CalculatorCodon counts, frequency per thousand, RSCU and GC3Open calculatorORF FinderOpen reading frames in all six frames, ATG to stopOpen calculatorIUPAC Ambiguity Code ToolDecode ambiguity codes and count the sequences they representOpen calculatorSequence Comparison and Alignment ToolPercent identity by global alignment or position by positionOpen calculatorGC Content Profile (Sliding Window)GC percentage along a sequence in a moving windowOpen calculatorOligo Resuspension and Dilution CalculatorBuffer volume for a stock, and dilution to a working concentrationOpen calculatorOligo Concentration Calculator (A260)Oligo concentration from absorbance, and µM ⇄ ng/µLOpen calculatorOligo and Primer AnalyzerLength, GC, Tm, weight and a design-guideline check for a primerOpen calculatorPrimer Hairpin and Dimer CheckerSelf-complementary stems and primer-dimer runs by sequence matchingOpen calculatorDegenerate Primer GeneratorBack-translate a peptide into a degenerate IUPAC primerOpen calculatorPrimer Pair AnalyzerTm match, GC, dimers and product size for a forward-reverse pairOpen calculator
PCR & qPCR
Master mixes, annealing temperature, efficiency and relative expression
PCR Master Mix CalculatorComponent volumes for any number of reactionsOpen calculatorqPCR ΔΔCt CalculatorRelative gene expression by the 2^−ΔΔCt methodOpen calculatorPCR Product Size CalculatorAmplicon length from primer positions, with 5′ tailsOpen calculatorPCR Annealing Temperature CalculatorOptimal annealing temperature from primer Tm and productOpen calculatorGradient PCR PlannerTemperature of each column in a gradient blockOpen calculatorqPCR Replicate Ct CalculatorMean, SD and fold spread of replicate Ct values, with flagsOpen calculatorqPCR ΔCt CalculatorΔCt and relative expression to a reference geneOpen calculatorqPCR Efficiency-Corrected Ratio (Pfaffl)Fold change when target and reference efficiencies differOpen calculatorqPCR Efficiency CalculatorAmplification efficiency from a dilution series or a slopeOpen calculatorqPCR Absolute Quantification CalculatorCopy number of unknowns from a standard curveOpen calculatorPCR Template Dilution CalculatorDilute a template to the amount you want per reactionOpen calculator
Cloning & CRISPR
Restriction digests, ligation, assembly, guide design and editing
Restriction Site FinderSites, cut positions and overhangs for named restriction enzymesOpen calculatorRestriction Digest PredictorFragment sizes for a single or multiple enzyme digestOpen calculatorRestriction Digest Reaction SetupVolumes of DNA, buffer, enzymes and water for a digestOpen calculatorLigation Calculator (Vector:Insert Ratio)Insert mass for a molar ratio, or the ratio from the masses you haveOpen calculatorPlasmid Size CalculatorSize of a recombinant plasmid after cloningOpen calculatorTransformation Efficiency CalculatorColony-forming units per microgram of DNAOpen calculatorGibson Assembly CalculatorFragment amounts and volumes for an overlap assemblyOpen calculatorGolden Gate Assembly CalculatorFragment amounts and volumes for a Type IIS assemblyOpen calculatorHomology Arm CalculatorExtract left and right homology arms around an edit siteOpen calculatorGuide RNA (gRNA) AnalyzerLength, GC content and sequence features of a CRISPR guideOpen calculatorCas9 Target Finder and PAM FinderFind PAM sites and protospacers for SpCas9, SpCas9-NG or SaCas9Open calculatorCas12a Target FinderFind TTTV PAM sites and protospacers for Cas12aOpen calculatorFrameshift CalculatorWill an insertion or deletion shift the reading frame?Open calculatorGenome Editing Efficiency CalculatorEditing rate from reads or clones, or from a T7E1 gelOpen calculator
Protein & Biochemistry
Protein mass, pI, extinction, assays, enzyme kinetics and binding
Protein and Peptide Molecular Weight CalculatorAverage or monoisotopic mass from a sequence, with end groupsOpen calculatorAmino Acid Composition CalculatorResidue counts, GRAVY, aliphatic index and charge contentOpen calculatorProtein Isoelectric Point (pI) CalculatorEstimated pI and the net charge at any pHOpen calculatorProtein Extinction Coefficient Calculatorε280 and A 0.1% from sequence, with optional concentrationOpen calculatorProtein Concentration Calculator (A280, A205)Concentration from absorbance, and mg/mL ⇄ µMOpen calculatorBradford Protein Assay CalculatorProtein concentration from a Bradford standard curveOpen calculatorBCA Protein Assay CalculatorProtein concentration from a BCA standard curveOpen calculatorLowry Protein Assay CalculatorProtein concentration from a Lowry standard curveOpen calculatorEnzyme Activity Calculator (Units, Specific Activity)U/mL from an absorbance rate, specific activity and unit conversionOpen calculatorMichaelis-Menten CalculatorRate at a given [S], or [S] for a target rate, with the curveOpen calculatorEnzyme Kinetics Calculator (Km, Vmax Fit)Nonlinear Michaelis-Menten fit, with Lineweaver-Burk for comparisonOpen calculatorIC50 CalculatorFour-parameter logistic fit, with Ki by Cheng-PrusoffOpen calculatorEC50 CalculatorFour-parameter logistic fit for a rising dose-response curveOpen calculatorProtein Binding Affinity (Kd) CalculatorKd and Bmax from a saturation curve, and fraction boundOpen calculatorGibbs Free Energy CalculatorΔG from K, from ΔH and ΔS, and under non-standard conditionsOpen calculatorEquilibrium Constant CalculatorK from concentrations, Ka ⇄ Kd ⇄ pKd, and K at another temperatureOpen calculator
Buffers & pH
pH, pKa, buffer capacity, titration curves and buffer recipes
pH Calculator (pH, pOH, Strong and Weak Acids)pH from [H⁺], pOH, strong acids and bases, or weak acids and basesOpen calculatorHenderson-Hasselbalch CalculatorBuffer pH, base-to-acid ratio, or pKaOpen calculatorpKa, Ka, pKb and Kb ConverterConvert between pKa, Ka, pKb and Kb of a conjugate pairOpen calculatorIonic Strength CalculatorIonic strength and Davies activity coefficients from the ions presentOpen calculatorOsmolarity CalculatorOsmolarity and osmotic pressure from solutes and dissociationOpen calculatorBuffer Capacity CalculatorBuffer capacity β, and the pH change after adding acid or baseOpen calculatorTitration Curve CalculatorpH against volume for a weak, strong or polyprotic acid titrated with baseOpen calculatorPhosphate Buffer Calculator (Sodium and Potassium)Masses of the mono- and dibasic salts for a phosphate buffer at a target pHOpen calculatorCitrate Buffer CalculatorCitric acid and trisodium citrate for a buffer at pH 3 to 6Open calculatorTris Buffer Calculator (Tris-HCl)Tris base and HCl for a target pH, with the temperature effectOpen calculatorPBS Recipe CalculatorSalt masses for 1×, 10× or 20× phosphate-buffered salineOpen calculatorTE Buffer Calculator (Tris-EDTA)Tris base, EDTA and HCl for TE at 1×, 10× or 100×Open calculatorAcetate Buffer CalculatorAcetic acid and sodium acetate for a buffer at pH 3.8 to 5.8Open calculator
Analytical Chemistry
Absorbance, calibration curves, detection limits, recovery and replicate statistics
Calibration Curve Calculator (Standard Curve)Linear fit, residuals and an unknown with its uncertaintyOpen calculatorBeer-Lambert Law CalculatorAbsorbance, concentration or ε, and absorbance ⇄ % transmittanceOpen calculatorSpectrophotometer Dilution CalculatorDilute a too-dark sample into the instrument's linear rangeOpen calculatorColony Count Calculator (CFU/mL)CFU/mL from plate counts at several dilutions, weighted over twoOpen calculatorELISA Standard Curve Calculator (4PL)Four-parameter logistic fit and sample concentrationsOpen calculatorLimit of Detection and Quantitation CalculatorLoD and LoQ from a calibration curve (ICH) or blanks (CLSI)Open calculatorPercent Recovery CalculatorRecovery of a spike or a standard, with biasOpen calculatorReplicate Measurement Statistics (SD, %RSD, SE, CI)Mean, SD, %RSD, standard error and 95% CI of replicatesOpen calculatorZ-Score CalculatorZ-score, percentile and probability, or the value for a ZOpen calculatorOutlier Screening Tool (Grubbs, Tukey, Modified Z)Flag suspect values with three standard screensOpen calculator
Statistics
Descriptive statistics, tests, regression, effect sizes, ROC and agreement
Descriptive Statistics CalculatorMean, median, mode, variance, SD, SE, CV, quartiles, skewnessOpen calculatorPercent Change and Fold Change CalculatorPercent change, fold change, log fold change and percent differenceOpen calculatorConfidence Interval CalculatorCI for a mean (t or z) and for a proportion (Wilson, exact, Wald)Open calculatorLinear Regression CalculatorSlope, intercept, R², standard errors, intervals, residuals and predictionOpen calculatorCorrelation Calculator (Pearson and Spearman)Pearson r or Spearman ρ with a confidence interval and p-valueOpen calculatort-Test Calculator (Welch, Student, One-Sample)Two-sample t-test with CI for the difference and effect sizeOpen calculatorPaired t-Test CalculatorPaired t-test on before-and-after or matched measurementsOpen calculatorOne-Way ANOVA CalculatorANOVA table, η², Levene's test and group summariesOpen calculatorChi-Square Test CalculatorIndependence or goodness of fit, with Yates, Fisher's exact and Cramér's VOpen calculatorEffect Size CalculatorCohen's d, Hedges' g, odds ratio and risk ratio with intervalsOpen calculatorROC Curve and AUC CalculatorROC curve, AUC with Hanley-McNeil interval, and the best thresholdOpen calculatorBland-Altman Analysis CalculatorBias, limits of agreement and their intervals for two methodsOpen calculator
Cell Culture
Counting, viability, seeding, passaging and growth
Trypan Blue Cell Count CalculatorViable cell concentration and viability from a trypan blue countOpen calculatorMOI Calculator (Multiplicity of Infection)Virus volume for a target MOI, or the MOI from a volume, with Poisson sharesOpen calculatorCulture Medium Supplement CalculatorVolumes of serum and supplements for a bottle of complete mediumOpen calculatorCell Freezing Calculator (Cryopreservation)Cells, freezing medium and DMSO for a batch of vialsOpen calculatorHemocytometer Cell Counting CalculatorCells per mL from a hemocytometer countOpen calculatorTotal Cell Count CalculatorTotal and viable cells in a suspensionOpen calculatorCell Viability Calculator (Trypan Blue)Percent viability from live and dead countsOpen calculatorCell Dilution CalculatorDilute a cell suspension to a target densityOpen calculatorCell Seeding CalculatorSuspension and medium for a plate of wellsOpen calculatorCells per cm² Seeding Density CalculatorCells needed for a vessel at a given seeding densityOpen calculatorSplit Ratio CalculatorSuspension and medium per vessel when passagingOpen calculatorCell Doubling Time CalculatorDoubling time from two cell countsOpen calculatorPopulation Doubling Level CalculatorPopulation doublings and cumulative PDL per passageOpen calculatorCell Confluence CalculatorEstimated confluence and time to reach a targetOpen calculator
Microbiology
Plate counts, optical density and growth rate
Antibiotic Stock and Working Concentration CalculatorPowder for a stock solution, and stock to add to medium or agarOpen calculatorMcFarland Standard CalculatorApproximate CFU/mL of a McFarland suspension and its dilution to a targetOpen calculatorCFU Calculator (Colony-Forming Units per mL)Viable count from a plate count and dilutionOpen calculatorOD600 to Cell Density CalculatorEstimate bacterial cell density from optical densityOpen calculatorBacterial Growth Rate CalculatorSpecific growth rate and doubling timeOpen calculator
Biomedical Engineering
Centrifuge, ECG, infusion, sensor, signal and measurement-error calculators
RCF to RPM Centrifuge CalculatorConvert between rpm and × g for any rotorOpen calculatorNyquist Sampling Rate CalculatorMinimum sampling rate and alias frequencyOpen calculatorOhm's Law CalculatorVoltage, current, resistance and powerOpen calculatorCentrifuge k-Factor and Pelleting Time Calculatork-factor, pelleting time, and run time between rotorsOpen calculatorECG Heart Rate CalculatorHeart rate from the R-R interval, grid boxes or a counted stripOpen calculatorQTc Calculator (Bazett, Fridericia and more)Heart-rate-corrected QT by four published formulasOpen calculatorBMI CalculatorBody mass index with the WHO adult categoriesOpen calculatorBody Surface Area CalculatorBSA by the Mosteller, Du Bois, Haycock and Gehan-George formulasOpen calculatorIV Flow Rate CalculatormL per hour from a volume and a time, or time and volume from a rateOpen calculatorDrip Rate CalculatorDrops per minute for a gravity infusion setOpen calculatorWeight-Based Infusion Rate CalculatorPump rate from a dose per kg per minute and a concentrationOpen calculatorPressure Unit ConvertermmHg, kPa, cmH₂O, psi, bar, atm and moreOpen calculatorTemperature ConverterCelsius, Fahrenheit, Kelvin and RankineOpen calculatorLaboratory Unit ConverterVolume, mass, length, time, pressure, electrical units and moreOpen calculatorDevice Battery Life CalculatorRun time, battery size, and energy use of a deviceOpen calculatorFrequency and Period CalculatorHertz, period, angular frequency and cycles per minuteOpen calculatorSampling Frequency CalculatorSampling rate, record size and frequency resolutionOpen calculatorSignal-to-Noise Ratio CalculatorSNR in dB from amplitudes, powers or mean and standard deviationOpen calculatorDecibel CalculatorRatios to dB, dB to ratios, and dBm to powerOpen calculatorSensor Sensitivity CalculatorSlope, offset and non-linearity from calibration pointsOpen calculatorCalibration Error CalculatorError at each point, as % of reading and of full scale, against a toleranceOpen calculatorPercent Error CalculatorPercent error of a measured value against an accepted oneOpen calculatorAccuracy and Precision CalculatorBias, standard deviation, %RSD and total error from repeatsOpen calculatorADC Resolution CalculatorLSB size, ideal SNR, bits needed, and effective bitsOpen calculator
These tools do the arithmetic; they do not replace a protocol, a validated method or your own judgement, and they are not for clinical or diagnostic use. Found an error or want a calculator added? Reach the maintainer from the footer.